Every time I’m explaining the intricacies of new technologies to networking engineers, I try to use analogies with older well-known technologies, trying to make it simpler to grasp the architectural constraints of the shiny new stuff.
Unfortunately, most engineers younger than ~35 years have no idea what I’m talking about – all they know are Ethernet, IP and MPLS.
Just to give you an example – here’s a slide from my SDN workshop.
Read more ...Last week I ran two SDN workshops, and in both of them the participants were busy taking notes as I explained the intricacies of concepts like SDN, NFV and network automation, and tools like OpenFlow or BGP.
However, how often did you revisit notes taken at a presentation and kept wondering “what exactly was he trying to say?” … or felt like the training you attended was like drinking from a fire hose and you missed most of the good stuff?
You won’t have that problem during the Miami SDN/NFV/SDDC retreat.
Read more ...Another week, another ExpertExpress session, as is often the case focusing on two data centers with stretched VLANs spanning both of them. However, this one was particularly irksome, as the customer ran a firewall cluster stretched across two locations.
I gave the customer engineers my usual recommendations:
Read more ...SD-WAN is all the rage these days (at least according to software-defined pundits), but networking engineers still build DMVPN networks, even though they are supposedly impossibly-hard-to-configure Rube Goldberg machinery.
To be honest, DMVPN is not the easiest technology Cisco ever developed, and there are plenty of gotchas, including the problem of default routing in Phase 2/3 DMVPN networks.
Read more ...While researching for another blog post, I stumbled upon this speech by Winston Churchill:
When the situation was manageable it was neglected, and now that it is thoroughly out of hand we apply too late the remedies which then might have effected a cure. There is nothing new in the story. It is as old as the Sibylline Books. It falls into that long, dismal catalogue of the fruitlessness of experience and the confirmed unteachability of mankind. Want of foresight, unwillingness to act when action would be simple and effective, lack of clear thinking, confusion of counsel until the emergency comes, until self-preservation strikes its jarring gong -these are the features which constitute the endless repetition of history.
Obviously mr. Churchill wasn't talking about IPv6 but about way more serious matters… but it's also obvious he was right abut the unteachability of mankind.
After ARIN ran out of IPv4 address space (in a totally uncontrolled “let’s party till it’s over” way) US enterprise IT shops (RFC 6919) OUGHT TO learn how to spell IPv6 (US service providers are already ahead of the pack).
You may also decide to ignore IPv6 indefinitely, but do keep in mind that consultants love panicking clients.
Read more ...Jim Small asked me what I thought about the Future of Networking Packet Pushers podcast with Douglas Comer. I decided to listen to it while driving toward one of my recent hikes, and it was a great decision– it was the best Packet Pushers podcast I listened to in a long while.
Read more ...Reiss Romoli, the fantastic organizers of my SDN/NFV event in Rome, Italy in late October are offering you a free personal ipSpace.net subscription – a saving of $299 or approximately EUR 270.
All you have to do to qualify is (A) download and fill in the registration form, (B) send it to Reiss Romoli and (C) pay before attending the webinar.
Yeah, I know the PDF form says “fax it back” – everyone has to use the tools that work best in their environment.
Hope we'll meet in warm and sunny Rome in a few weeks!
During my recent SDN workshop one of the attendees asked me “How do you build carrier-grade (5 nines) cloud infrastructure with VMware NSX?”
Short answer: You don’t… and it’s a wrong question anyway.
Read more ...A while ago I started discussing the intricate technical details of fibbing (an ingenious way of implementing traffic engineering with traditional OSPF) with Laurent Vanbever and other members of his group, and we decided to record a podcast on this topic.
Things never go as planned in a live chat, and we finished talking about another one of his projects – software defined Internet exchange point (SDX), the topic of Episode 41 of Software Gone Wild.
Read more ...A year ago I was a firm believer in the unlimited powers of Software-Defined Data Centers and their ability to simplify workload migrations. After all, if you can use an API to create any data center object, what’s stopping you from moving the workload running in a data center to another location.
As always, there’s a huge difference between theory and reality.
Read more ...I got into an interesting discussion with a fellow networking engineer trying to understand the impact of a switch failure in a L2/L3 data center fabric (anything from Avaya’s fabric or Brocade’s VCS Fabric to Cisco’s FabricPath, ACI or Juniper’s QFabric) on MAC and ARP tables.
Here’s my take on the problem – have I missed anything?
Read more ...Did you know that many networking engineers use ipSpace.net webinars (and subscription) to prepare for the job interviews?
Here’s one of their success stories (name changed for obvious reasons):
Read more ...In a recent blog post Tom Hollingsworth made a great point: we should refocus from fighting one fire at a time to preventing fires.
I completely agree with him. However…
Read more ...Bryan would love to get hands-on SDN experience and sent me this question:
I was recently playing around with Arista vEOS to learn some Arista CLI as well as how it operates with an SDN controller. I was wondering if you know of other free products that are available to help people learn.
Let’s try to do another what-is-out-there survey.
Read more ...Dinesh Dutt started his part of the Data Center Fabrics Update webinar with “what is Cumulus Linux all about” and “what data center architectures does it support” and then quickly jumped into details about the base technologies used by Cumulus Linux: MLAG and IP routing.
Not surprisingly, the MLAG part generated tons of questions, and Dinesh answered all of them, even when he had to say “we don’t do that”.
If you’ve been a networking engineer (or a sysadmin) for a few years, you must be pretty familiar with DHCP and might think you know everything there is to know about this venerable protocol. So did I… until I read the article by Chris Marget in which he answers two interesting questions:
When I wrote my stretched VSAN post, I thought VSAN uses asynchronous replication across WAN. Duncan Epping quickly pointed out that it uses synchronous replication, and I fixed the blog post.
The “What about latency?” question immediately arose somewhere in my subconscious, but before I could add that thought to the blog post (because travel), Anders Henke wrote a lengthy comment that totally captured what I was thinking, so I’m including it in its entirety:
Read more ...One of my subscribers asked me: “My subscription is valid till early December. How could I renew it now (due to budgetary reasons)?”
While I already had the process to do just that, there was no link that one could use (you had to know the correct URL). I’ve fixed that – you’ll find the renewal link on the first page of my.ipSpace.net
Another week, another story from the SDN land, this time The Register reporting on AT&T plans. Even though there are almost no details in the story, the headline boasts that “SDN is eating vendors’ lunch”, prompting SDN hopefuls on LinkedIn groups to claim that “the promise of SDN is fast coming to fruition.”
Not so fast.
Read more ...